How it works
Firestore stores documents in collections, and apps talk to it directly through the Firebase SDKs rather than through a server of your own. Listeners push every change to connected clients instantly, and the SDKs cache data so an app keeps working without a connection and syncs when it comes back.
Access is controlled by security rules that Google checks on every read and write. Billing is per operation: you pay for document reads, writes and deletes plus storage, so a screen that reads thousands of documents on every visit gets expensive. Queries are deliberately limited so that they always stay fast.
Cloud Firestore pros and cons
Pros
- Real-time sync and offline support built into the SDKs
- No servers to run, and it scales automatically
- Works hand in hand with Firebase Auth, Functions and Hosting
- Generous free daily quota for small apps
Cons
- Per-read pricing can surprise you as traffic grows
- Limited queries: no joins, and some filters need composite indexes
- Data and rules are tied to Google Cloud, which makes leaving harder
When to use Cloud Firestore
Pick it when
- Chat, live dashboards and collaborative apps that need instant updates
- Mobile apps that must work offline
- Small teams that want no backend servers at all
Skip it when
- Reporting, complex filters or relational data, where SQL fits better
- Read-heavy pages where per-read billing would add up
Cloud Firestore pricing
Free tier
Free daily quota (1 GiB stored, 50,000 reads, 20,000 writes and 20,000 deletes a day). Beyond that, pay per operation on the Blaze plan, typically a few cents per 100,000 reads.
Cloud Firestore pricing page (opens in a new tab)Approximate, checked September 2026.What the other tools cost
Cloud Firestore vs the alternatives
Related terms
More in Databases and storage
Document and key-value